diff --git a/litex/soc/cores/spi_opi.py b/litex/soc/cores/spi_opi.py index 1e43882b9..45f477677 100644 --- a/litex/soc/cores/spi_opi.py +++ b/litex/soc/cores/spi_opi.py @@ -18,9 +18,7 @@ class S7SPIOPI(Module, AutoCSR, AutoDoc): sim = False, spiread = False, prefetch_lines = 1): - self.intro = ModuleDoc(""" - Intro - ******** + self.intro = ModuleDoc("""Intro SpiOpi implements a dual-mode SPI or OPI interface. OPI is an octal (8-bit) wide variant of SPI, which is unique to Macronix parts. It is concurrently interoperable with SPI. The chip @@ -300,14 +298,13 @@ class S7SPIOPI(Module, AutoCSR, AutoDoc): ), ] - self.architecture = ModuleDoc(""" - Architecture - ************** + self.architecture = ModuleDoc("""Architecture The machine is split into two separate pieces, one to handle SPI, and one to handle OPI. SPI - ===== + ----- + The SPI machine architecture is split into two levels: MAC and PHY. The MAC layer is responsible for: @@ -333,7 +330,8 @@ class S7SPIOPI(Module, AutoCSR, AutoDoc): Thus holding "req" high can allow the PHY to back-to-back issue cycles without pause. OPI - ===== + ----- + The OPI machine is split into three parts: a command controller, a Tx PHY, and an Rx PHY. The Tx PHY is configured with a "dummy cycle" count register, as there is a variable length @@ -389,6 +387,7 @@ class S7SPIOPI(Module, AutoCSR, AutoDoc): - pre-fetch is aborted because bus_adr and next read address don't match and FIFO is reset RxPHY: + - while CTI==2, assemble data into 32-bit words as soon as EMPTY is deasserted, present a bus_ack, and increment the next read address pointer - when CTI==7, ack the data, and wait until the next bus cycle with CTI==2 to resume